Let us discuss about each.RLWL Remote Location Wait List:
This is also known as Running Line Waiting List or Road-Side Location Waiting List. RLWL means Ticket is issued for intermediate stations (between the originating and terminating stations) because usually these are the most important towns or cities on that particular route. This type of tickets will be given a separate priority and confirmations will depend on the cancellations of a destination confirmed ticket, and these tickets don’t even have RAC Provision. For this type of ticket there are less chances of confirmation.
For example, if you have booked a RLWL ticket from Jaipur to Delhi in a train which starts from Ahmedabad and ends at Chandigarh, your ticket will be confirmed or RAC when a confirmed passenger cancels his ticket from Jaipur to Delhi.

RLGN Remote Location General Wait List:
RLGN ticket will be issued for an intermediate station (which is not the originating station for the train) to destination/nearby destination station. It will come under general wait list which have more chances of confirmation. If someone from that place cancels the ticket you will get confirmed i.e this type of tickets will have RAC Provision.

RQWL Request Waiting List:
If a ticket is to be booked from an intermediate station to another intermediate station, and if it is not covered by the general quota or by the remote location quotas or pooled quota, the request for the ticket may go into a RQWL. A ticket on this list is usually confirmed only when there is a confirmed ticket for a passenger travelling from the originating station to that intermediate station. If you want to travel from an intermediate point to the terminating station the same process is followed when if there is no Remote Location Quota defined for that intermediate point.

PQWL Pooled Quota Wait List:
This is a waiting list ticket against pooled quota. It is shared by several small stations in a particular region. E.g., Tiruppur, Salem.
Pooled Quotas normally operate only from the originating station of a route, and there is only one Pooled Quota for the entire run. The Pooled Quota is generally allotted for passengers travelling from the originating station to a station short of the terminating station, or from an intermediate station to the terminating station, or between two intermediate stations.
The chance of getting this ticket confirmed is very less. This type of tickets will be confirmed only after confirming other waiting list tickets which usually does not happen in most of the cases.

PQWL is used mainly in Southern and Western India reservation systems.
Eg: 2723 Andhra Pradesh Express has three quotas, for Secunderabad – New Delhi, Secunderabad – Nagpur, and Secunderabad – Bhopal
Here is an example. If you were to book a ticket from Bangalore (SBC) to Rajamundry(RJY) on the Guwahati Express (2509), then you would get tickets assigned from the Pooled Quota.
Waiting lists from this PQ quota appear as PQWL on the ticket.
PQ status is generally given if the original quota runs in WL, or doesn’t have sufficient number of confirmed berths available.

For example if four people are on a travel, their status is as below.
Passenger 1 -Confirmed, PQ
Passenger 2 -Confirmed, PQ
Passenger 3 -Confirmed, GN
Passenger 4 -Confirmed, GNWL

Due to the unavailability of sufficient number of confirmed berths, the first two passengers are confirmed against PQ, third against GN and then the concerned Waitlist applicable across the journey .
However in rare cases, PNR having single passenger are also placed against PQ in the same way.

GNWL General Wait List:
Tickets are issued by booking offices of the originating station and other nearby stations is known asGNWL. This is the waiting list for general quota.

CKWL Tatkal Quota Wait List:
This is the waiting list for tatkal tickets. Your ticket gets confirmed only if some persons who booked tatkal ticket cancels. So the chance of getting ticket confirmed is very less if your waiting list position is more (>10).
The difference between normal waiting list and CKWL is that when the normal waiting list moves up it goes to RAC category whereas for CKWL when the waiting list moves up you can expect confirmed berth.